Novel differential scanning calorimetry (DSC) application to select polyhydroxyalkanoate (PHA) producers correlating 3-hydroxyhexanoate (3-HHx) monomer with melting enthalpy

• Published in: Bioprocess and biosystems engineering Vol. 47; no. 10; pp. 1619 - 1631
• Main Authors: Jung, Hee Ju, Kim, Byungchan, Choi, Tae-Rim, Oh, Suk Jin, Kim, Suwon, Lee, Yeda, Shin, Yuni, Choi, Suhye, Oh, Jinok, Park, So Yeon, Lee, Young Sik, Choi, Young Heon, Yang, Yung-Hun
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.10.2024; Springer Nature B.V
• Subjects: Biodegradability; Biodegradation; Biotechnology; Calorimetry; Chemistry; Chemistry and Materials Science; Composition; Cupriavidus; Differential scanning calorimetry; Enthalpy; Environmental Engineering/Biotechnology; Food Science; Gas chromatography; Industrial and Production Engineering; Industrial Chemistry/Chemical Engineering; Magnetic properties; Melting; Microorganisms; Monomers; NMR; Nuclear magnetic resonance; Polyhydroxyalkanoates; Polyhydroxyalkanoic acid; Polymers; Research Paper; Sequential analysis; Thermal properties; Thermodynamic properties; DSC; Melting enthalpy; 3HHx; P(3HB; P(3HB-co-3HHx); Cupriavidus
• ISSN: 1615-7591; 1615-7605; 1615-7605
• DOI: 10.1007/s00449-024-03054-9

Polyhydroxyalkanoate (PHA) is an environmental alternative to petroleum-based plastics because of its biodegradability. The polymer properties of PHA have been improved by the incorporation of different monomers. Traditionally, the monomer composition of PHA has been analyzed using gas chromatography (GC) and nuclear magnetic resonance (NMR), providing accurate monomer composition. However, sequential analysis of the thermal properties of PHA using differential scanning calorimetry (DSC) remains necessary, providing crucial insights into its thermal characteristics. To shorten the monomer composition and thermal property analysis, we directly applied DSC to the analysis of the obtained PHA film and observed a high correlation ( r 2  = 0.98) between melting enthalpy and the 3-hydroxyhexanoate (3-HHx) mole fraction in the polymer. A higher 3-HHx fraction resulted in a lower melting enthalpy as 3-HHx provided the polymer with higher flexibility. Based on this, we selected the poly(3-hydroxybutyrate- co -3-hydroxyhexanoate) (P(3HB- co -3HHx)) producing strain from Cupriavidus strains that newly screened and transformed with vectors containing P(3HB- co -3HHx) biosynthetic genes, achieving an average error rate below 1.8% between GC and DSC results. Cupriavidus sp. BK2 showed a high 3-HHx mole fraction, up to 10.38 mol%, with T m  (℃) = 171.5 and Δ H of T m (J/g) = 48.0, simultaneously detected via DSC. This study is an example of the expansion of DSC for PHA analysis from polymer science to microbial engineering.